


A Tale of Two Gasters

by DeterminationIsNotCrash



Category: Undertale (Video Game)
Genre: Alternate Universe - Gaster Blaster (Undertale), Gen, spoilers for both Algernon and Breaking Through Fate
Language: English
Status: Completed
Published: 2020-01-08
Updated: 2020-01-08
Packaged: 2021-02-19 07:02:39
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,180
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22173679
Author URL: https://archiveofourown.org/users/DeterminationIsNotCrash/pseuds/DeterminationIsNotCrash
Summary: A W.D. Gaster and Papyrus from separate worlds take a look at what things would have been like if the Wingdings Gasters of their timelines had switched places.(Written as of Algernon Chapter 18)
Kudos: 4





	A Tale of Two Gasters

**Author's Note:**

  * Inspired by [algernon](https://archiveofourown.org/works/20002504) by [parsnipit](https://archiveofourown.org/users/parsnipit/pseuds/parsnipit). 



> "Key":  
> Impact is a GB!Papyrus from a version of Breaking Through Fate where he failed against Wingdings.  
> Doc is the Wingdings Gaster from Algernon.  
> Hopebringer is the Wingdings Gaster from Breaking Through Fate.

Wingdings ‘Doc’ Gaster had never felt more suspicious of someone in his life. As the two skeletons walked back to the landship that was their home base, his eyes never broke away from the sight of the half-Blaster walking next to him. Which made it awfully hard to eat the gourmet ice cream cone, but this was far more important. “…Say, Impact…”

“Yes, Doc?”

“Do you need something from me?”

The usual calm and cool smile of the sunglass-wearing raptor remained on his face as he spoke. “What makes you say that?”

“For a start, you’re usually _never_ this nice to me. A fishing trip, an amusement park visit, _and_ an All-You-Can-Eat dinner, _all_ paid for by you? Don’t misunderstand, I truly enjoyed today, but if there’s anything you need from me, you can just say it outright.”

“Is it so wrong that I want to spend quality time with a loving father figure?” The Papyrus Gaster from another world chuckled, casually leaning against the entrance of the ship. “Besides, where else would I want to be on Father’s Day?”

“Father’s Day is in two months.”

“…!” For a moment, he was frozen in place, rigid and stiller than a statue. It was as if he was a video that someone just pressed pause on.

Doc was considering doing the old ‘kick it until it works’ trick that people used to do in the past with old computers, before the half-beast let out the breath he was holding and resumed talking. “…Very well, you saw through me. I need to ask you to test something that was always on my mind.”

Dread started to gnaw in the older Gaster’s ribcage. When Impact said things like that, that was usually a cause for great concern.

Noticing the change in his friend’s mood, Impact swiftly elaborated, practically doing a butterfly impression with the floating mechanical hands he could summon. “Please don’t misunderstand! This isn’t something with any potential for physical harm! It’s just a Virtual Reality program.”

The only thing the unfamiliar term drew out of Doc’s mind was a big question mark. “Virtual… Reality…?”

“Ah, I forgot, your timeline hadn’t progressed that far yet.” The half-Blaster made his way into the ship, gesturing for Doc to follow. Once they arrived at the recreational area, Impact asked the more humanoid skeleton to sit down on the sofa, then swiftly disappeared into the corridor. A few minutes later, he returned with two strange, translucent visors.

“These are VR headsets – think of them like television or games, but on a completely different level of immersion. You can directly connect your senses to the world of the game or movie! They’re useful for escapism, entertainment, _and_ combat training!

“These ones have a special program installed by a friend. It’s a ‘world simulator’ – using advanced AI technology, you can create characters and scenarios to play through, then generate summary movies of how they interact. You can use it to create fiction, make your ideal world, or… see an approximation of how certain real-life scenarios could have played out.”

“Go on…” Doc nodded, not liking a single bit of where this was going.

“To get to the point of what I would like you to do… I always had on my mind, what would have happened if you and my father were in each other’s shoes. You and he are like night and day, in terms of personalities. If you went through what he did… would my world have found salvation?”

“But how will it benefit us? It’s rather unhealthy to get lost in the ‘what-ifs’, ‘maybes’, and ‘if-onlys’.”

“We’ll be able to understand each other better. After what happened earlier, I believe it might be necessary.” He winced as he stated this, before his gaze moved to _through_ Gaster. “…And we can understand the threat we’re up against. Of course, my father isn’t here now, so I can roleplay what he would have done.”

Gaster weighted up the options in his mind. There didn’t _seem_ to be any risk of harm… “Very well, I’ll do it. Just tell me what I need to do with writing the scenarios.”

A grin spread across Impact’s muzzle. “Thank you. We can start by…”

* * *

Doc awoke with a start, his vision darkened slightly by the visor. His head spun slightly – the transition from the immersive VR program to the real world was very disorientating. The old man removed the headset, then checked the time. True to Impact’s words, although several hours had passed in the simulation, only half an hour had passed in reality.

The relatively large raptor beast next to him was stirring, too – seemed that his simulation had finished, too. Impact removed his visor, and greeted the retired doctor with another calm smile. “How was it?”

“Very… interesting. What happens now?”

“I’ll load the data into the computer, and we can see the summary movie generated. I’d like to see yours first.” Without waiting for an answer, the Papyrus almost too eagerly took the headset and plugged it into one of the group’s laptops, which was also connected to the rec room’s television. A few clicks of the mouse, a few taps on the keyboard, and the movie of what happened started to play…

* * *

True to Impact’s prediction, if Doc was in Hopebringer’s – the codename Impact’s father used to go by before revealing himself – place, Impact’s life would have been much happier. Just like the Blaster project in Doc’s world, both the Apocalypse Cannon and Darkness projects were almost instantly cancelled.

This naturally meant that there was no Flowey – Alphys never employed as the Royal Scientist, and no Fragments to animate the spirits of the deceased. Children’s souls were still taken, with Asgore’s declaration of war unaffected by the change in timeline.

When Frisk arrived, Chara did not exist to guide him, and neither did his Determination, the power to let him achieve what he did in the real world. Nevertheless, Frisk could still survive. Sans still met Toriel… and because of Doc-as-Hopebringer’s guidance in making sure he _kept_ to the promise they made, the human boy could safely navigate the Underground and, after much effort, diffuse tensions between the two races.

Unwilling to kill anyone else to get their way, and without a weapon to break the Barrier, no one who entered the Underground ever left. And yet, they still managed to find a small amount of happiness beneath the earth.

When Hopebringer finally passed away at a ripe old age, he was surrounded by his family and friends. Even though his children never saw the surface… Even though monsterkind never went free… his life was a calm, peaceful one.

* * *

It wouldn’t have surprised any of the people in the party – both the two in the rec room and those currently not present – that the movie was enough to move Impact to tears. The misty-eyed Blaster was currently dabbing at his face with a handkerchief. “Ah, it’s happening again…”

Doc carefully leaned over towards the skeletal raptor. “Will you be alright?”

The Papyrus finished drying his tears, before facing the other skeleton with a small smile. “Yes, thank you. I won’t get too lost in the life my father and I could have had…” The small smile grew into a determined grin. “I’ll focus on reality. A reality that I can change.”

Doc returned Impact’s grin, before pouring himself some tea and turning back to the television screen. Now it was time for the scenario with Impact playing Hopebringer playing Doc.

What would Hopebringer have done in his situation? Would Impact’s perception of his father lead to a bias in his decisions?

Upon the movie’s start, the camera view illuminated a bright blue sky – they were on the Surface.

Doc tilted his head to the side in confusion. “Oh? We’re starting at the end?”

Impact’s floating mechanical hands were clasped in front of his muzzle, not unlike a character from a television show Doc saw Alphys watching once. “It must be a flash forward.”

When the camera panned down, Doc could barely restrain himself from doing a spittake with his drink, liquid dribbling down his chin and onto the floor.

The man onscreen was _him_! He didn’t have any of the effects from the aging that resulted from giving his life force away to his children. Then that could only mean…

A self-important, egotistical smile was on ‘his’ face, as he walked down an isle. A row of massive Blaster beasts were standing at each end of him, bowing as he approached a throne. The emperor took his place on the seat, and with that, the camera zoomed out to reveal a massive crowd, bowing before him. Had all of monsterkind gathered there…?

* * *

For better or for worse, Hopebringer had a far greater drive than Doc, while lacking any sense of restraint or morals. The fires of tragedy in Hopebringer’s past forged him into someone who would do anything, seize any opportunity for power and control – it didn’t matter what he did, or whose lives he trampled over… Just as long as for once… just once, in his life… he got his way.

With the opportunities afforded to him by Doc’s Blaster Project, it was like winning the lottery for several years straight. When Sans said his first word, Impact-playing-Hopebringer-as-Doc was ecstatic – not because he had a son, but because he had an _intelligent_ weapon. The key to producing more super soldiers.

Sans, being… himself… turned out to be quite the handful. Even with Doc’s ‘discipline device’ – a collar that could either administer a powerful electric shock whenever the tool disobeyed its master, or simply detonate a bomb if it became too much of a nuisance – he still found ways to disobey as much as he could. Eventually, he was deemed a ‘faulty prototype’ and disposed of accordingly, like a rag that was so dirty, it wasn’t even worth cleaning.

Doc swiftly moved onto creating obedient, unquestioning living weapons. The skeleton who would have become Papyrus in another world was instead mass produced into an army, beaten and conditioned from birth to become like a pack of ravenous wolves that only existed to rip apart the innocent sheep.

Ambition burning inside of him, Doc decided to overthrow the incompetent King Asgore. The Royal Guard (and civilians who took up arms such as Undyne’s parents) rushed to stop him… but their efforts were all in vain.

It was like every bitter nerd’s dream – the protein-chewing, weight-lifting jocks who would have looked down on him in any other situation didn’t even stand a chance. Violently ripped into blood and guts, then collapsing into the worthless dust they truly were.

With the souls, he stormed the Surface, and finally managed to enact his revenge on the world that wronged him. With the power of the human souls and his Blaster army, all those he considered undesirable were purged from the planet. What remained was an eternal heaven on Earth for those who sided with him… and an eternal hell, for all who dared oppose him.

* * *

The movie didn’t just send a shiver down Doc’s spine. His entire body trembled with fury at the horrible acts performed by his alternate timeline counterpart. _This_ was the man whose grudge created the distortions tainting the world of Impact’s present – and by extension, the entire multiverse? The man whose sole desire was to hold the world in the palm of his hand?

The endless loop of “All hail Gaster!” – three words that Doc never wanted to hear together – came to an end alongside the credits.

Impact gently placed a hand on the old man’s shoulder. “I ask you to commit the sights within this video to memory – if we can’t match my father, in will or power… this will soon be reality.”

Doc gulped, before slowly nodding. ‘Hopebringer’… the Wingdings Gaster of Impact’s world… had to be stopped at all cost. The stakes were too high. Doc had already given the majority of his life force and power away to his children… no, they were still sapping it now.

But before he faded away entirely, there was still something he had to do with what remained of his life. Though, the direct combat he could leave to the others. His fight lay elsewhere, a place that wasn’t the battlefield.

“This technology… it’s very useful. Just by inputting our choices into the simulation, it created full-fledged movies. May I get in touch with this friend of yours? What was their name?”

“H.D. Chaos.” At the change in Doc’s expression from mentioning it (it could be universally translated into the phrase ‘Are you serious?’), Impact pre-emptively clarified. “…Yes, just like ‘Impact’, it’s a pseudonym.”

After much deliberation – weighing whether informing the public of ethics was worth the media exposure it drew to his family – Doc decided to create a full-fledged scenario, with the help of the others in the group. A generated film chronicling the events of his original world, to ensure that the doors to hell were never opened again. That film… was called _Algernon_.


End file.
